At present, two different technologies are used for assembling electric harnesses, depending on the temperatures that exist in their zones of use. When the maximum temperature in said zones does not exceed 150° C., the electrical connection wires and cables are generally protected by means of a structure comprising a textile braid forming a first layer protecting the electric wires and cables, a tubular braid surrounding the textile braid and providing electromagnetic shielding, and an outer sheath of heat-shrink polymer and having, at its end, an endpiece made of a heat-shrink polymer and serving both to protect the end of the shielding braid on the tubular metal or composite connection part and also to connect with the outer sheath of that connection part. That structure has the advantage of accommodating relatively short radii of curvature, but its ability to withstand temperature is limited to 150° C.
In zones where the temperature is higher and might reach a peak value of 260° C., the electric wires and cables are protected by a tubular structure that comprises an inner sheath of polytetrafluoroethylene (PTFE), a metal braid for electromagnetic shielding surrounding said sheath, and a textile braid surrounding the shielding braid and made of a material that withstands high temperatures, e.g. aramid fibers, the end of said structure being held by a mechanical collar against a metal or composite connection part.
The drawback of that structure is that it is heavier than the preceding structure and does not accept short radii of curvature.